Lighting elements based on the chemiluminescent emission generated by the mixing of two liquids are already known.
The principle and the techniques for the production of chemiluminescent light are fully described in U.S. Pat. No. 4,678,608 which is incorporated in the present description as a reference.
The chemiluminescence is produced by reaction in the liquid phase of an activator such as hydrogen peroxide with a fluorescent agent and an oxalate. Other secondary compounds may also be present, generally fluorescent agents modifying the characteristics of the emitted light.
In addition to the very widespread chemiluminescent lighting elements that include one of the liquids in a glass tube capable of breaking and of thus expanding its contents into a chamber already equipped with the second liquid, there have more recently been put on the market chemiluminescent lighting elements with two distinct chambers, each made of a translucent synthetic material. These elements have the advantage of avoiding the use of glass.
Among these, there is one that consists of placing the liquids in a tube of transparent synthetic material in which a disk is placed transversely, separating the said tube into two chambers or compartments, each containing one of the liquids. Mixing takes place when there is caused, from the outside or the article, the rotation of the disk, which then lies flat and lets the liquids pass.
In general, the disk is given a diameter slightly greater than the internal diameter of the tube so that the wall of the tube, deformed elastically at right angles with the disk, exerts a centripetal pressure along the whole edge of the edge of the disk, thus ensuring tightness.
It has been found, surprisingly, that under certain conditions, it is sufficient to increase the pressure in one of the two chambers with respect to that prevailing in the other chamber, to cause rotation of the disk. In principle, if the centripetal pressure ensured by the elastic extension of the tube wall in the region in which it grips the disk is applied in a uniform and isotopic manner, the increase in pressure in one chamber as compared with the other will only have the effect of causing a displacement of the disk parallel to itself, not its rotation.
Without wishing to be bound to specific explanations, it is known that a goodly number of synthetic materials capable of constituting the tube wall actually do not show a perfect elastic behavior and therefore show a certain degree of plasticity. If, consequently, during installation of the disk in its transverse position, forces are exerted on the inner walls of the tube, at the point where the disk is supported, that are not uniformly distributed over the circumference, the edge of the disk may be driven more strongly into the wall at certain points than at others, and at least part of these differential indentations will remain permanently as a result of the plasticity. If a uniform hydraulic pressure is later exerted on one of the faces of the disk, it will not be displaced parallel to itself. The disk is actually driven further into the wall at certain points, which will show greater opposition to displacement, thus creating a torque causing rotation of the disk.
In another known embodiment, the adjacent chambers are separated by a plug, which is in contact on one side with the fluid present in the first chamber and on the other side with the fluid present in the second chamber. This plug yields when the pressure in the first of the two chambers appreciably exceeds that in the other chamber. This result can be obtained by making the first chamber more deformable than the other. When the whole of the element is immersed to a certain depth in water, it receives the required hydrostatic pressure. The use of this type of element, is of course, appreciated when one is looking for automatic lighting at a certain depth of immersion in the sea. Lighting outside water is also possible by manual compression of the deformable chamber.